Cervical cancer is the second most common malignant tumor among women in the world, following breast cancer. There are about 500,000 newly reported cases worldwide every year, and nearly 250,000 people die of this disease annually. Cases in developing countries account for approximately ⅔ of the total. Cervical cancer is also prevalent in China. The cases of cervical cancer in China account for 10% of the total. Studies showed that Human Papilloma Virus (HPV) is closely associated with cervical cancer, and is an important carcinogenic factor and one of the prerequisites for causing cervical cancer. It is shown that more than 100 types of HPV can cause infection in skin (skin type) or in mucosa of respiratory tract and anal-genital tract (mucosal type), and more than 40 types of HPV can cause infection in cervices. HPV types are divided into the following two groups depending on the benign, premalignant or malignant pathological changes induced thereby: (1) group of low cancerogenic risk, containing such as types 6, 11, 42, 43, and 44; and (2) group of high cancerogenic risk, containing such as types 16, 18, 31, 33, and 45. Therefore, early detection and correct typing of HPV infections are essential for the prevention and treatment of cervical cancer.
Current HPV detection methods are mainly divided into the following groups. (1) Cytological examination, which makes diagnosis on the basis of change in cell morphology by using cytological examination of cervical smear or thin-prep cell test (TCT). As for HPV infection, koilocytosis, dyskeratosis and condylomata like basal cell can be seen under microscopy. Its shortcoming lies in low sensitivity and specificity in the diagnosis of HPV infection. (2) Immunohistochemical method, which further confirms HPV infection by detecting the capsid antigen of HPV. The positive reaction thus obtained is definitely located and the result is reliable. However, capsid antigens are not produced until HPV-DNA is replicated and mature. Therefore, subjects diagnosed as negative cannot be taken as unaffected by HPV. The method has low sensitivity. (3) Real-time Fluorescence Quantitative PCR (FQ-PCR), which primarily employs a fluorescence detection PCR Instrument. In the method, a fluorescent group is added to the PCR reaction system, and the amplification product produced in each cycle during PCR is real-time monitored by accumulation of the fluorescent signal, thereby accomplishing the quantitation of the initial concentration of the template. The method has a low throughput. (4) Hybrid capture method (primarily HC-II system), which is the only clinic method for detection of HPV DNA approved by US FDA, and is approved by European CE and Chinese SFDA. The method employs specific specimen collectors and containers, a RNA probe of 8000 bp in full length and a specific first antibody, both of which have been granted a patent right. The mechanism for the method is that the nucleic acid probe is hybridized to the HPV DNA of the subject to be tested, and the detection is carried out based on the amplified signals by chemical fluorescence or enzymatic reactions. The nucleic acid probes used in the method are mainly divided into two classes: nucleic acid probes as directed to low-risk HPV and nucleic acid probes as directed to high-risk HPV. The method can be used in primary screening of HPV, but can neither determine the specific type of HPV nor determine multiple infections.
The sensitivity of HPV detection can be increased and the false negative rate can be reduced by using the above detection methods in combination. However, the cost for the combination of these methods was high, and thus the combination of these methods is just feasible in the HPV detection and screening of cervical carcinoma in economy developed areas. For economy less developed areas, especially mountainous areas and most of rural areas, there is a big limitation on using said detection methods in combination. Therefore, there is a need to develop a suitable and low-cost HPV detection method.
In another aspect, the currently known HPV detection methods, such as the detection methods as described above, have low throughput. When conducting HPV detection to samples in large scale, application of said methods are time-consuming and labor-consuming, and the cost thereof is high. Therefore, there is also an urgent need in the art for a new high-throughput and low-cost HPV detection method.